TULSA, Okla. — Wesley Witherspoon was on his back, arms stretched wide as his face fixed a “How could you miss that?” expression on the same lonesome ref whom Memphis fans already were calling every unsavory name in the book.

Witherspoon’s attempt at a 2-footer to tie the game in the final seconds had been sent in a wayward direction by Arizona All-American Derrick Williams — a shot-block heard ’round Tulsa and Tucson and certainly much of Texas. No. 5 seed Arizona survived, 77-75, and advanced to a Sunday meeting with the No. 4 seed Longhorns, who must know by now that saving the day is among the many things Williams does exceedingly well.

“You could say I got fouled,” Witherspoon said afterward, “or you could say I wasn’t.”

OK, we’ll take the bait. He wasn’t. Not even close.

What else did Williams, a 6-8 sophomore forward widely projected as a 2011 NBA lottery pick, do to push Arizona into the third round?

Most dramatically, he hit the 3-pointer with 3:51 remaining that broke a 65-65 tie — the Wildcats never trailed again.

But it wasn’t just the game-turning plays that made Williams special on this day. He led his team with truly remarkable patience and unselfishness.

Clearly among the best few players in the entire Tournament, Williams took only 11 shots; for much of the game, he was essentially a decoy as Memphis attacked him with a variety of defenses.

“And yet,” his coach, Sean Miller, said, “as oftentimes is the case with a great player, the final stat sheet read, ‘Derrick Williams, 22 points and 10 rebounds.’ He did what he was supposed to do.”

What he’ll have to do next is tangle with a Longhorns front line that is powerful and dynamic on defense. Freshman forward/center Tristan Thompson had seven blocks in UT’s second-round win. Senior forward Gary Johnson has the quickness and experience to be a huge factor vs. Williams.

Texas probably won’t have to be as creative as Memphis was. Tigers coach Josh Pastner actually threw his young, thin team into a box-and-one to try to contain the Pac-10 player of the year. A box-and-one on a big guy?

“Never seen that before,” Williams said.

“There is a reason why I voted for him for national player of the year,” Pastner explained. “And my vote doesn’t change after today’s performance.”

Williams’ offense was actually pretty quiet vs. Memphis, perhaps because the underdog Tigers did so much celebrating after baskets that it felt like they were winning even when they weren’t. It’s probably fair to say the Tigers were more fired up, while the Wildcats were calmer and steadier.

Thing is, the competition is about to get a lot stiffer.

“And if we don’t come to play,” Williams said, “it could be a long night. But I don’t plan on that happening.”